While the oil valve worked perfectly, water valve has some irregularity, linked with the small gap, the shape irregularity, the surface roughness and the poorer lubrication conditions in the water hydraulics compared to the oil system. However, the observed irregularity of the movement of the spool in the water hydraulic valve had almost no influence on the movement of the piston rod of the water cylinder, which is a very promising result for future research on water hydraulics.
F.02 Acquisition of new scientific knowledge
The proportional water hydraulic control valve was developed and manufactured as specimen. Based on the measured results of characteristics at the transient phenomena of this valve we can conclude that this valve can be used in water power-control hydraulic systems. The duration tests, that were carried out, prove that we can expect acceptable useful life of such valves also in the terms of high and dynamic working loadings.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 762116However, in order to ensure a satisfactory useful life time of the proportional 4/3 directional control valve, an optimal tribological pair is required in the valve. With this aim in mind, we carried out preliminary tribological tests of different material-pairs lubricated with additive-free distilled water. The tested materials were stainless steel, PI, PEEK and Al2O3. The results of the preliminary tribological tests of different material pairs are described in this paper.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 10167835The doctor dissertation shows the possibility of the usage of tap water as hydraulic fluid instead of traditionally used mineral hydraulic oil. Comparative tests in two systems were carried out. The two systems have above mentioned two fluids. The universal, double unique test rig was designed, constructed and built up and at the same time a new water 4/3 proportional water control sliding type valve too. The results of measurements of transient phenomena and the comparison of results between the water and the oil part of the double system – test rig are presented.
D.09 Tutoring for postgraduate students